W元素掺杂CeO2非均相电芬顿催化剂高效处理含油污水

制备了W元素掺杂的CeO₂复合材料, 通过扫描电子显微镜、 透射电子显微镜、 X射线衍射和X射线光电子能谱等对W-CeO₂-0.4催化材料进行表征. 结果表明, 具有不规则片状形貌的W元素掺杂CeO₂复合材料提高了单一CeO₂的类芬顿催化效果; 将其作为非均相电芬顿催化剂对含油污水的处理效果明显优于电吸附和物理吸附过程. 进一步的参数优化处理实验发现, 在电压为4 V, pH=3时, 采用W-CeO₂-0.4作为催化剂的条件下, 对含油污水的净化能力在90 min内达到了99.8%, 总有机碳(TOC)去除率达到了约90%, 化学需氧量(COD)去除率达到了76%.     

An Unprecedented Kernel Growth Mode and Layer-Number-Odevity-Dependent Properties in Gold Nanoclusters

Kernel atoms of Au nanoclusters are packed layer-by-layer along the [001] direction with every full (001) monolayer composed of 8 Au atoms (Au₈ unit) in nanoclusters with formula of Au_8n+4(TBBT)_4n+8 (n is the number of Au₈ units; TBBTH=4-tert-butylbenzenelthiol). It is unclear whether the kernel atoms can be stacked in a defective-layer way along the [001] direction during growth of the series of nanoclusters and how the kernel layer number affects properties. Now, a nanocluster is synthesized that is precisely characterized by mass spectrometry and single-crystal X-ray crystallography, revealing a layer stacking mode in which a half monolayer composed of 4 atoms (Au₄ unit) is stacked on the full monolayer along the [001] direction. The size and the odevity of the kernel layer number influence the properties (polarity, photoluminescence) of gold nanoclusters. The obtained nanocluster extends the previous formula from Au_8n+4(TBBT)_4n+8 to Au_4n+4(TBBT)_2n+8 (n is the number of Au₄ units).     

Molecularly Engineered Macrophage-Derived Exosomes with Inflammation Tropism and Intrinsic Heme Biosynthesis for Atherosclerosis Treatment

Atherosclerosis (AS) is a major contributor to cardiovascular diseases worldwide, and alleviating inflammation is a promising strategy for AS treatment. Here, we report molecularly engineered M2 macrophage-derived exosomes (M2 Exo) with inflammation-tropism and anti-inflammatory capabilities for AS imaging and therapy. M2 Exo are derived from M2 macrophages and further electroporated with FDA-approved hexyl 5-aminolevulinate hydrochloride (HAL). After systematic administration, the engineered M2 Exo exhibit excellent inflammation-tropism and anti-inflammation effects via the surface-bonded chemokine receptors and the anti-inflammatory cytokines released from the anti-inflammatory M2 macrophages. Moreover, the encapsulated HAL can undergo intrinsic biosynthesis and metabolism of heme to generate anti-inflammatory carbon monoxide and bilirubin, which further enhance the anti-inflammation effects and finally alleviate AS. Meanwhile, the intermediate protoporphyrin IX (PpIX) of the heme biosynthesis pathway permits the fluorescence imaging and tracking of AS.     

Observation of the mica surface by atomic force microscopy

Freshly cleaved mica and a mica surface treated with pure water and dilute-salt solution have been investigated by Atomic Force Microscopy (AFM). On the bare mica surface (after repeated scanning), small dots and islands were observed. The disappearance of these dots and islands has also been captured by AFM. We believe these structures to be condensed water. The water meniscus between AFM tip and mica surface is considered as the source of this water structure. On the mica surface treated with pure water and dilute-salt solution, network structures are frequently observed by AFM.     

Effect of wall temperature on hypersonic turbulent boundary layer

Turbulent boundary layers at Mach 4.9 with the ratio of wall temperature to recovery temperature from 0.5 to 1.5 are investigated by means of direct numerical simulation. Various fundamental properties relevant to the influence of wall temperature on Morkovin’s scaling, standard and modified strong Reynolds analogies, and coherent vortical structures have been studied. It is identified that the scaling relations proposed for cool and adiabatic wall conditions, such as Morkovin’s scaling and the modified strong Reynolds analogy, are also applicable for hot wall condition. Moreover, the relation between the density and temperature fluctuations under the second-order approximation is derived and verified to provide a reliable prediction. Based on the analysis of coherent vortical structures, it is found that the orientation of vortex core can be quantitatively determined by means of the vector with its direction and modulus using the local strain direction and the imaginary part of the eigenvalue of velocity gradient tensor, respectively. As the increase of wall temperature, the spanwise distance between the two legs of hairpin vortex increases, and the mean swirling strength and the angle of vortical structure with respect to the wall plane also increase in the inner layer. The statistical properties relevant to vortical structures are nearly insensitive to the wall temperature in the outer layer.     

Comb-Channels of Left–Right-Handed Circular Polarizations from Coupled Resonators

In order to obtain multi-channels of left–right-handed circular polarizations, we design a structure with coupled magnetic resonators and study its transmission properties using the tight-binding model and the 4×4 transfer matrix method. The incidence of a linearly polarized light can be split into two groups of resonant peaks. One group corresponds left-handed circular polarization and the other group corresponds to right-handed circular polarization. By properly adjusted magnetization, the two group can be merged into one group, in which the channels of left-handed circular polarization and right-handed circular polarization are alternately arranged in the transmission spectrum. Thus, we can obtain the comb-channels of left–right-handed circular polarizations.     

Submanifolds with parallel normalized mean curvature vector in a unit sphere

Let M ⁿ be an n-dimensional closed submanifold of a sphere with parallel normalized mean curvature vector. Denote by S and H the squared norm of the second fundamental form and the mean curvature of M ⁿ , respectively. Assume that the fundamental group \({\pi_{1}(M^{n})}\) of M ⁿ is infinite and \({S\, \leqslant\, S(H)=n+\frac{n^{3}H^{2}}{2(n-1)}-\frac{n(n-2)H}{2(n-1)}\sqrt{n^{2}H^{2}+4(n-1)}}\), then S is constant, S = S(H), and M ⁿ is isometric to a Clifford torus \({S^{1}(\sqrt{1-r^{2}})\times S^{n-1}(r)}\) with \({r^{2}\leqslant \frac{n-1}{n}}\).     

Pd-catalyzed asymmetric allylic alkylation of indoles and pyrroles by chiral alkene-phosphine ligands

A variety of chiral binaphthyl-based terminal-alkene-phosphine hybrid ligands were synthesized in four steps with (S)-BINOL as a starting material and utilized for the Pd-catalyzed enantioselective allylic alkylations of indoles and pyrroles to afford the desired products in high yields with good to excellent ee's.     

Highly efficient "grafting from" an α-helical polypeptide backbone by atom transfer radical polymerization

Because of their favorable biodegradability, biocompatibility, regular secondary structures, and stimuli‐responsiveness, synthetic polypeptides have attracted more and more attention in the biomedical material field. In this work, a novel thermo‐responsive graft polypeptide, poly(L ‐glutamate)‐graft‐poly(2‐(2‐methoxyethoxy)ethyl methacrylate) (PLG‐g‐PMEO₂MA), is prepared through a combination of ring‐opening polymerization and atom transfer radical polymerization. The structure of PLG‐g‐PMEO₂MA is confirmed by FT‐IR, ¹H NMR, and GPC analyses. The phase transition temperature of PLG‐g‐PMEO₂MA is adjustable by varying the NaCl concentration in aqueous solution. PLG‐g‐PMEO₂MA adopts α‐helical conformations both in aqueous solution at 25 and 60 °C and even in the solid state. In addition, PLG‐g‐PMEO₂MA forms stimuli‐responsive micelles with an α‐helical core and a thermo‐responsive shell in water.